This investigation is the first stage of a study concerning the development of topography in the cerebral cortex through late prenatal and early postnatal life. The initial step, proposed here, will determine the normal topographic organization of the somatosensory cortex in the adult rabbit that later will be correlated with the anatomical connections of this region. The data will be generated through: (1) physiologic mapping of the somatosensory cortex, in normal adult New Zealand white rabbits and (2) a light microscopic examination of connections with the somatosensory cortex using radiolabelling and retrograde enzymatic transport techniques. This investigation will establish a model system that can be used to study the mechanisms controlling normal development of the mammalian nervous system and abnormal development leading to the production of human congenital disorders and behavioral disabilities.